The present invention relates to coating of high-potency sweeteners and other gum ingredients with aqueous solutions of zein, particularly for use in chewing gum, and more particularly to improve the stability of the sweetener in the gum and/or control the release of the sweetener or other ingredient from the gum.
Zein is a protein compound that has been known as a coating agent. Most commonly, zein is mixed with alcohol to make a spray dry encapsulating solution. However, the use of alcohol in such spray coating techniques presents special problems, especially where the coated product is used in food products such as chewing gum. First, a food grade alcohol must be used. Second, because alcohol is flammable, extra safety precautions must be used.
Coating with zein or other encapsulating agents is useful to protect sensitive gum ingredients. Also, coating may be helpful to control the release of material from chewing gum. High-potency sweeteners are particularly of interest in chewing gum, and coating is thus of interest to improve the stability of the sweetener in chewing gum and/or control its release in chewing gum. Numerous patents address different sweeteners, coating agents and coating techniques.
For example, U.S. Pat. No. 4,597,970 to Sharma et al. teaches a process for producing an agglomerated sweetener wherein the sweetener is dispersed in a hydrophobic matrix consisting essentially of lecithin, a glyceride, and a fatty acid or wax having a melting point between 25.degree. C. and 100.degree. C. The method disclosed uses a spray-congealing step to form the sweetener-containing matrix into droplets, followed by a fluid bed second coating on the agglomerated particles.
U.S. Pat. Nos. 4,515,769 and 4,386,106, both to Merrit et al., teach a two step process for preparing a delayed release flavorant for chewing gum. In this process, the flavorant is prepared in an emulsion with a hydrophilic matrix. The emulsion is dried and ground, and the resulting particles are then coated with a water-impermeable substance.
U.S. Pat. No. 4,230,687 to Sair et al. teaches a process for encasing an active ingredient to achieve gradual release of the ingredient in a product such as chewing gum. The method described involves adding the ingredient to an encapsulating material in the form of a viscous paste. High-shear mixing is used to achieve a homogeneous dispersion of the ingredient within the matrix, which is subsequently dried and ground.
U.S. Pat. No. 4,139,639 to Bahoshy et al. teaches a process of "fixing" aspartame by co-drying (by spray drying or fluid bed coating) a solution containing aspartame and an encapsulating agent, such as gum arabic, to thereby surround and protect the aspartame in the gum during storage.
U.S. Pat. No. 4,384,004 to Cea et al. teaches a method of encapsulating aspartame with various solutions of encapsulating agents using various encapsulation techniques, such as spray drying, in order to increase the shelf-stability of the aspartame.
U.S. Pat. No. 4,634,593 to Stroz et al. teaches a method for producing controlled release sweeteners for confections, such as chewing gum. The method taught therein involves the use of a insoluble fat material which is mix mulled with the sweetener.
U.S. Pat. Nos. 2,154,482 and 2,489,147 use zein as a gum base ingredient. U.S. Pat. Nos. 3,010,953 and 4,224,219 disclose a modified zein to make it more water soluble. These patents also indicate that high pH aqueous zein films are not stable, as the alkali degrades the protein film.
U.S. Pat. No. 3,068,062 discloses the use of aqueous zein to make textile fibers. U.S. Pat. No. 3,116,206 discloses coacervated zein in aqueous solutions plus polymers like CMC to form an encapsulant. Other patents disclose the use of zein for coating, but use zein and/or alcohol/aqueous mixtures to solubilize zein for encapsulation. These patents are French Patent Nos. 2,117,506 and U.S. Pat. Nos. 4,194,013; 4,137,300; 4,384,004; and 4,474,749.
It would be of benefit to use zein as a coating agent for chewing gum ingredients without using alcohol as a solvent.